Person:
Iribas Pardo, Haritz

Last Name

Iribas Pardo

First Name

Haritz

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Estadística, Informática y Matemáticas

ORCID

0000-0003-4260-2379

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810714

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Now showing 1 - 10 of 22

Open Access
Effects of pump pulse extinction ratio in Brillouin optical time-domain analysis sensors
(Optical Society of America, 2017) Iribas Pardo, Haritz; Mariñelarena Ollacarizqueta, Jon; Feng, Cheng; Urricelqui Polvorinos, Javier; Schneider, Thomas; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We report on two previously unknown non-local effects that have been found to impair Brillouin optical time-domain analysis (BOTDA) sensors that deploy limited extinction ratio (ER) pump pulses. The first one originates in the increased depletion of the pedestal of the pump pulses by the amplified probe wave, which in turn entails a reduced amplification of the probe and a measurement distortion. The second effect is due to the interplay between the transient response of the erbium-doped fiber amplifiers (EDFA) that are normally deployed to amplify the pump and the pedestal of the pump pulses. The EDFA amplification modifies the pedestal that follows the pulses in such a way that it also leads to a distortion of the measured gain spectra after normalization. Both effects are shown to lead to non-local effects in the measurements that have similar characteristics to those induced by pump pulse depletion. In fact, the total depletion factor for calculations of the Brillouin frequency shift (BFS) error in BOTDA sensors is shown to be the addition of the depletion factors linked to the pump pulse as well as the pedestal. A theoretical model is developed to analyze both effects by numerical simulation. Furthermore, the effects are investigated experimentally in long-range BOTDA sensors. The pedestal depletion effect is shown to severely constrain the probe power as well as the minimum ER of the pulses that can be deployed in BOTDA sensors. For instance, it is shown that, in a long-range dual-probe BOTDA, an ER higher that 32-dB, which is above that provided by standard electro-optic modulators (EOM), is necessary to be able to deploy a probe power of -3 dBm, which is the theoretical limit for that type of sensors. Even more severe can be the limitation due to the depletion effect induced by the EDFA transient response. It is found that the impairments brought by this effect are independent of the probe power, hence setting an ultimate limit for the BOTDA sensor performance. Experimentally, a long-range BOTDA deploying a 26-dB ER EOM and a conventional EDFA is shown to exhibit a BFS error higher than 1 MHz even for very small probe power.
Open Access
Enhanced tolerance to pulse extinction ratio in Brillouin optical time domain analysis sensors by dithering of the optical source
(SPIE, 2015) Iribas Pardo, Haritz; Urricelqui Polvorinos, Javier; Sagüés García, Mikel; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We demonstrate the relaxation of the stringent requirements placed on the pulse extinction ratio in long-range Brillouin optical time-domain analysis sensors (BOTDA) by modulating the wavelength of the laser source that is used to generate both pump and probe waves. This modulation makes the counter-propagating pulse pedestal and probe waves to become correlated only at certain locations in the fiber, thus reducing the gain experienced by the probe wave, which is precisely the process that limits the performance in long-range BOTDAs. Proof-of-concept experimental results in a 20-km sensing link demonstrate a 6-dB reduction of the required modulator extinction ratio.
Open Access
Second-order non-local effects mitigation in BOTDA sensors by tracking the BFS profile
(SPIE, 2017) Mompó Roselló, Juan José; Iribas Pardo, Haritz; Urricelqui Polvorinos, Javier; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
We demonstrate a technique to mitigate the residual second-order non-local effects in Brillouin optical time-domain analysis (BOTDA) sensors in which the Brillouin frequency shift (BFS) profile is not uniform along the fiber. It is based on adding a wavelength modulation to the probe wave that makes it track the average BFS found along its way. Using this method we are able to inject a total probe wave power of 15 dBm in a 120-km sensing fiber link, which, to the best of our knowledge, is the highest probe power ever demonstrated in a long-range BOTDA sensing fiber link. The enhancement in the detected signal-to-noise ratio brought by the use of such power provides 2-MHz BFS measurement precision at the end of the 120-km sensing link with 3-m spatial resolution, all without the need to resort to additional means such as the use of coding or Raman gain.
Open Access
Mejoras en sensores distribuidos basados en dispersión Brillouin estimulada en fibra óptica
(2015) Iribas Pardo, Haritz; Loayssa Lara, Alayn; Sagüés García, Mikel; Escuela Técnica Superior de Ingenieros Industriales y de Telecomunicación; Telekomunikazio eta Industria Ingeniarien Goi Mailako Eskola Teknikoa
El presente trabajo fin de máster se ha llevado a cabo con el objetivo de desarrollar un sistema sensor de fibra óptica distribuido, capaz de monitorizar la deformación unitaria y variaciones de temperatura, basándose en el efecto de dispersión Brillouin estimulada en fibra óptica. Mejorando y solventando algunas de las limitaciones que manifiestan estos sensores hoy en día. Dado el auge actual en el que se encuentran los sensores Brillouin ópticos basados en el análisis del dominio del tiempo, el trabajo se ha centrado en ese tipo de sensores. Para ello, se ha realizado una revisión bibliográfica del estado del arte, obteniendo una visión más detallada de este tipo de sensores. Tras realizar dicha revisión, se ha concluido que esta tecnología es muy interesante para la realización de sensores de monitorización de grandes estructuras, en las cuales sean de interés las medidas de deformación unitaria y temperatura. En particular, los sensores Brillouin basados en el dominio del tiempo están en plena evolución, incluso ofrecen la posibilidad de realizar medidas a altas frecuencias de muestreo, que era la carencia de sensores anteriores. Sin embargo, cabe destacar que actualmente, las soluciones comerciales de este tipo de sensores son muy costosas y complejas, debido a los numerosos dispositivos que son necesarios para su correcto funcionamiento. Además, cuentan con algunas limitaciones como el efecto de la polarización del campo óptico en la medida, la resolución espacial alcanzada, la precisión de medida o el rango dinámico de la misma. Una vez realizada la revisión del estado del arte, se ha procedido a investigar novedosas técnicas para paliar algunos de los defectos de estos sensores. Una de las mejoras propuestas, se basa en aplicar una novedosa técnica para obtener todas las señales ópticas necesarias para este tipo de sensor mediante una única fuente óptica. De este modo, se simplifica el esquema de estos sensores, reduciendo el número de componentes necesarios para su desarrollo, de manera que se obtiene una reducción significativa en el coste final del sensor. Por otro lado, y con el objetivo de mejorar una de las principales limitaciones por las que se ven afectadas este tipo de sensor para medidas de larga distancia, se ha propuesto y se ha demostrado, por primera vez, un sistema de medida capaz de relajar los estrictos requerimientos de relación de extinción del pulso. Aplicando dicha técnica, se obtiene una mejora en la precisión de los sensores, sin suponer ello un incremento en el coste del sensor. En todo momento, las derivaciones teóricas de los esquemas de mejora propuestos han sido contrastadas con demostraciones experimentales en el laboratorio. Además, cabe destacar el hecho de que los sistemas propuestos han obtenido excelentes resultados, mejorando los sistemas actuales.
Open Access
Detrimental effects in Brillouin distributed sensors caused by EDFA transient
(Optical Society of America, 2017) Feng, Cheng; Iribas Pardo, Haritz; Mariñelarena Ollacarizqueta, Jon; Schneider, Thomas; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
We investigate the deleterious effect and the error in Brillouin optical time-domain analyzers induced by the combination of a low extinction ratio pulse generation with the transient behavior of erbium-doped fiber amplifiers.
Open Access
Pulse coding linearization for Brillouin optical time-domain analysis sensors
(Optical Society of America, 2018) Mariñelarena Ollacarizqueta, Jon; Iribas Pardo, Haritz; Loayssa Lara, Alayn; Institute of Smart Cities - ISC
We introduce a simple method to extend the performance of pulse coding techniques in their application to Brillouin optical time-domain analysis sensors (BOTDA). It is based on applying a simple logarithmic processing on the detected probe wave that compensates the deviation from linearity of the sensor response for long code lengths. The technique ensures that the accumulated effect of a sequence of pulses is equal to the linear addition of the effects of the individual components, which is the essential condition to ensure a correct decoding of the probe gain measurement. We experimentally demonstrate the compensation of the Brillouin frequency shift error induced by the accumulated gain nonlinearity. Furthermore, a proof-of-concept 80 km sensing link within a total 200 km fiber loop demonstrated a better than 2 MHz precision with 2 m spatial resolution.
Open Access
Zuntz optikoan oinarritutako sentsoreen prestazioen muga-efektu berria, egituren egoera monitorizatzea helburu
(Udako Euskal Unibertsitatea, 2017) Iribas Pardo, Haritz; Mariñelarena Ollacarizqueta, Jon; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Brillouin denbora-eremu optikoaren analisian (BOTDA) oinarritutako sentsoreak estruktura handien (120 km luzerako estrukturak) deformazioa eta tenperatura neurtzeko gaitasuna dute, metro bateko bereizmen espazialarekin. Lan honetan, sentsorearen merkatu-prezioa handitu gabe bereizmen espazial txikiagoa lortzeko beharrezkoa litzatekeen teknika erabiltzeak dituen efektu kaltegarriak aztertu egin dira. Izan ere, pultsu azkar bat sortzeko beharrezkoak diren Mach-Zehnder modulagailu elektrooptikoek iraungitze-ratio (ER) txikia dute. Horiek horrela, aztertu egin da pultsatutako seinalea sortzeko sorgailuak duen ERaren eragina BOTDA sentsoreen prestazioetan, akats handiak sortzen direla ondorioztatuz.
Open Access
Contribution to the advancement of Brillouin optical time-domain analysis sensors
(2018) Iribas Pardo, Haritz; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Distributed fiber optic sensors (DFOS) are becoming an increasingly used technology to monitor the integrity of structures. This is due to the fact that this technology can be embedded within the structure and provide distributed information of several relevant parameters for the structure, such as stress, temperature or strain. In DFOS the fiber itself is the transducer, and the measurement of a given parameter is provided continuously along the fiber at a particular spatial resolution, without blind spots. This is the main advantage of DFOS compared to other sensing technologies, the fact that DFOS provide information of a given parameter over thousands or hundreds of thousands of positions along the optical fiber. Conversely, other sensing technologies only give information over the specific points where they are installed, that is to say, they are point sensors. This characteristic of distributed fiber sensors makes them enormously interesting when many points of a structure need to be monitored. In this case, a single distributed fiber sensor can replace many point sensors, which considerably reduces the cost per sensing point when monitoring large structures. In addition, due to the properties of the optical fiber, these sensors have a better performance compared to other kind of sensors. Among other important features, DFOS present a low signal loss, electromagnetic interference immunity, remote sensing and multiplexing capabilities, light weight, and are chemically passive, which make them a very attractive technology for field measurements. Therefore, DFOS have the added advantage of being electrically, magnetically, and chemically passive, so that can be placed in harsh environments, such as nuclear plants or areas with gas concentration, where, due to the possibility of a short circuit, electronic sensors cannot be placed. Al these characteristics make this technology unique. Among the different types of DFOS, those based on stimulated Brillouin scattering, and more specifically, those that build upon the Brillouin optical time-domain analysis (BOTDA) technique, are one of the most promising. The main characteristic that makes BOTDA sensors as promising, is the ability to perform distributed strain and temperature measurements over long distances at high spatial resolution. For the functioning of the sensor, the general interaction that takes place in the BOTDA technique involves two optical waves: a continuous wave probe and a counter-propagating pump pulse. The performance of the sensor response is limited, among others, by the maximum optical power of both waves that can be injected into the fiber. In this way, the main research line in BOTDA sensors is focused on the study of the physical limitations of the technique as well as the development of solutions to these constraints. Another important line relies on the simplification of the sensor setup so as to reduce the complexity and the cost of the sensor. This thesis dissertation contributes to the development of BOTDA sensors by means of different contributions in these two research lines. Several theoretical and experimental studies have been conducted to accurately determine the main limits to the sensor performance in terms of the maximum optical power of the pump and probe waves that can be used. One of the most important limitation in BOTDA sensors is the onset of non-local effects, which limits the maximum pump and probe waves power that can be injected in the fiber, and hence, the signal-to-noise ratio (SNR) at the receiver is worsen. The so-called non-local effects generate measurement errors, because the Brillouin spectra measured at distant locations depend on the interaction at previous positions in the fiber. In this research line, we have examined the effects caused by the limited extinction ratio (ER) of the pump pulse, finding that, among other impairments, it leads to the onset of a new non-local effect originated in the depletion of the pedestal of the pump wave. In addition, it has been found that the pedestal deformation caused by the transient response of erbium-doped fiber amplifiers, which are typically deployed to amplify the pump pulse, also constrains the performance of the sensor. Another contribution is the study of the techniques presented in the literature to mitigate the impairments caused by second-order non-local effects, which cause a frequency-dependent spectral deformation of the pulse. The findings of this study show that these techniques are only applicable when the Brillouin frequency shift (BFS) of the fiber is uniform, which is hard to find in real applications. Lastly, another subject of study is the limitations of the pump and probe optical power in coded-pump wave BOTDA configurations. We have observed that, in addition to some known limitations, there are two important restrictions that have to be taken into account: the onset of non-local effects and the non-linear amplification of the probe wave, both generated by the successive gain induced by the multiple pulses of the coded-pump wave. As a consequence of the findings of these studies, BOTDA configurations intended to solve these limitations have also been proposed during the thesis work. A technique to mitigate the constraints induced by the limited ER of the pump pulse has been presented. This method is based on adding a dithering to the optical source used to generate the two waves involved in the BOTDA sensor, so that the optical wavelength of both signals is modulated. In this way, the Brillouin interaction between the pedestal and the probe wavefronts become uncorrelated, and hence, the influence of the pedestal is greatly reduced. Another contribution is a technique focused on completely overcome the onset of second-order non-local effects. This method is based on continuously tracking the BFS distribution of the fiber, which combined with the probe-dithering method, has allowed, to the best of our knowledge, to inject the highest demonstrated probe wave power in a BOTDA sensor to date. In addition, in order to improve the SNR of the sensor, a novel BOTDA sensor has been proposed. This analyzer combines mono-color cyclic coding and probe-dithering techniques, so that the impairments caused by a coded pump wave are reduced, and hence, it is possible to increase the optical power and consequently enhance the sensing distance range. Finally, a novel simplified BOTDA sensor has been presented, which relies on passive optical filtering of the spectral components generated in a single optical source. In this way, the sensor setup is simplified reducing the number of optical devices, and therefore, the cost of the sensor is also reduced. This BOTDA configuration has been shown to have a performance comparable to more complex setups.
Open Access
Egituren egoeraren monitorizaziorako zuntz optikoan oinarritutako sentsore sinplifikatua
(Udako Euskal Unibertsitatea, 2015) Iribas Pardo, Haritz; Sagüés García, Mikel; Mariñelarena Ollacarizqueta, Jon; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Brillouin hedatuko denbora eremu optikoaren analisian (BOTDA) oinarritutako sentsoreak, estruktura handien (100 km luzerako estrukturak) deformazioa eta tenperatura neurtzeko gaitasuna dute. Lan honetan, BOTDA konfigurazio sinplifikatua aurkezten dugu. Erabilitako konfigurazioaren helburua sentsorearen prezioa murriztea da, detekzio prozesuan parte hartzen duten seinale optikoen sortze prozesua sinplifikatuz. Proposatutako teknika hau, iturri optiko bati irrati-maiztasun (IM) pultsu modulatu bat aplikatuz sortutako osagai espektralen iragazketa optiko pasiboan oinarritzen da. Laborategiko esperimentuek frogatzen dute tenperatura hedatuko neurriak 1,1 metroko erresoluzioarekin 5 km zuntz optikoan zehar
Open Access
Cost-effective Brillouin optical time-domain analysis sensor using a single optical source and passive optical filtering
(Hindawi Publishing Corporation, 2016) Iribas Pardo, Haritz; Urricelqui Polvorinos, Javier; Mariñelarena Ollacarizqueta, Jon; Sagüés García, Mikel; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We present a simplified configuration for distributed Brillouin optical time-domain analysis sensors that aims to reduce the cost of the sensor by reducing the number of components required for the generation of the two optical waves involved in the sensing process. Te technique is based on obtaining the pump and probe waves by passive optical filtering of the spectral components generated in a single optical source that is driven by a pulsed RF signal. Te optical source is a compact laser with integrated electroabsorption modulator and the optical filters are based on fiber Bragg gratings. Proof-of-concept experiments demonstrate 1m spatial resolution over a 20km sensing fiber with a 0.9MHz precision in the measurement of the Brillouin frequency shiſt, a performance similar to that of much more complex setups. Furthermore, we discuss the factors limiting the sensor performance, which are basically related to residual spectral components in the filtering process.